1. Field of the Invention
This invention is concerned with improvements in check valves, and more particularly is directed to the class of such valves having a self-sealing feature. The invention is meant primarily for use in catheters and similar medical applications involving the transport of fluids.
2. Description of the Prior Art
Catheters are frequently used in medical applications for conducting fluids to or from body cavities. In many cases catheters are provided with a cuff (inflatable balloon), suitable for engaging and sealing the wall of a body passage so as to limit passage of fluid to or from the body cavity to that passing through the catheter. For example, a tracheal catheter may be designed for insertion into the trachea and may include an inflatable balloon near the distal end for sealing the tracheal passage. It is important that the balloon be easily inflated and that it remain in the inflated condition for the desired length of time. For example, a tracheal catheter may be employed in connection with a surgical procedure extending over a significant period of time, and it is necessary that the balloon remain reliably inflated throughout this time. For this purpose it is conventional to provide a check valve in a tube connected to the balloon for inflation thereof. It is desirable that this check valve, which in this specification will hereinafter also be referred to as an inflation valve, be easily actuated when it is desired to supply fluid to the aforementioned balloon of the catheter or when it is desired to discharge the fluid therefrom, and it is desirable that the valve remain reliably sealed during the intervening period.
It is increasingly common that catheters of this type are intended to be disposable after a single use. Accordingly, it is desirable that such devices be of simple construction and inexpensive to manufacture. These requirements, of course, apply to the inflation valve which forms part of the disposable catheter. Many prior art inflation valves have three or more parts and have involved significant cost in manufacture and assembly. The prior art does include some two-piece inflation valves but these prior art two-piece valves have involved additional manufacturing operations or assembly problems which increase the cost and make them less desirable, therefore, for use as disposable items.
The valve of the present invention differs from those of the prior art in that it employs a highly simplified two-piece construction. This facilitates manufacture of the valve components and reduces manufacturing costs. The structure is such that a valve element seals firmly against a valve housing, insuring against undesired leakage of fluid therethrough, but the element is easily moved away from the housing, when desired, to interrupt the seal and allow the free flow of fluids through the valve in either direction.